Tonight I want to begin by congratulating the men and women of the 112th Congress, as well as your new speaker, John Boehner. And as we mark this occasion, we are also mindful of the empty chair in this chamber, and pray for the health of our colleague - and our friend - Gabby Giffords.

It's no secret that those of us here tonight have had our differences over the last two years. The debates have been contentious; we have fought fiercely for our beliefs. And that's a good thing. That's what a robust democracy demands. That's what helps set us apart as a nation.

But there's a reason the tragedy in Tucson gave us pause. Amid all the noise and passions and rancor of our public debate, Tucson reminded us that no matter who we are or where we come from, each of us is a part of something greater - something more consequential than party or political preference.

We are part of the American family. We believe that in a country where every race and faith and point of view can be found, we are still bound together as one people; that we share common hopes and a common creed; that the dreams of a little girl in Tucson are not so different than those of our own children and that they all deserve the chance to be fulfilled.

That, too, is what sets us apart as a nation.

'A shared responsibility'

Now, by itself, this simple recognition won't usher in a new era of cooperation. What comes of this moment is up to us. What comes of this moment will be determined not by whether we can sit together tonight, but whether we can work together tomorrow.

I believe we can. I believe we must. That's what the people who sent us here expect of us. With their votes, they've determined that governing will now be a shared responsibility between parties. New laws will only pass with support from Democrats and Republicans. We will move forward together, or not at all - for the challenges we face are bigger than party, and bigger than politics.

At stake right now is not who wins the next election - after all, we just had an election. At stake is whether new jobs and industries take root in this country, or somewhere else. It's whether the hard work and industry of our people is rewarded. It's whether we sustain the leadership that has made America not just a place on a map, but a light to the world.

We are poised for progress. Two years after the worst recession most of us have ever known, the stock market has come roaring back. Corporate profits are up. The economy is growing again.

But we have never measured progress by these yardsticks alone. We measure progress by the success of our people. By the jobs they can find and the quality of life those jobs offer. By the prospects of a small-business owner who dreams of turning a good idea into a thriving enterprise. By the opportunities for a better life that we pass on to our children.